From: Amir Goldstein <amir73il@gmail.com>
To: Miklos Szeredi <mszeredi@redhat.com>
Cc: overlayfs <linux-unionfs@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 19/35] ovl: readd reflink/copyfile/dedup support
Date: Tue, 17 Apr 2018 23:31:44 +0300 [thread overview]
Message-ID: <CAOQ4uxjKJHnM_ad9TnyQ8i0fUjEqCEG8ocPAs_L0oSraKhSEPA@mail.gmail.com> (raw)
In-Reply-To: <20180412150826.20988-20-mszeredi@redhat.com>
On Thu, Apr 12, 2018 at 6:08 PM, Miklos Szeredi <mszeredi@redhat.com> wrote:
> Since set of arguments are so similar, handle in a common helper.
>
> Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
> ---
> fs/overlayfs/file.c | 79 +++++++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 79 insertions(+)
>
> diff --git a/fs/overlayfs/file.c b/fs/overlayfs/file.c
> index 9670e160967e..39b1b73334ad 100644
> --- a/fs/overlayfs/file.c
> +++ b/fs/overlayfs/file.c
> @@ -352,6 +352,81 @@ long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
> return ret;
> }
>
> +enum ovl_copyop {
> + OVL_COPY,
> + OVL_CLONE,
> + OVL_DEDUPE,
> +};
> +
> +static ssize_t ovl_copyfile(struct file *file_in, loff_t pos_in,
> + struct file *file_out, loff_t pos_out,
> + u64 len, unsigned int flags, enum ovl_copyop op)
> +{
> + struct inode *inode_out = file_inode(file_out);
> + struct fd real_in, real_out;
> + const struct cred *old_cred;
> + int ret;
> +
> + ret = ovl_real_file(file_out, &real_out);
> + if (ret)
> + return ret;
> +
> + ret = ovl_real_file(file_in, &real_in);
> + if (ret) {
> + fdput(real_out);
> + return ret;
> + }
> +
> + old_cred = ovl_override_creds(file_inode(file_out)->i_sb);
> + switch (op) {
> + case OVL_COPY:
> + ret = vfs_copy_file_range(real_in.file, pos_in,
> + real_out.file, pos_out, len, flags);
Problem:
vfs_copy_file_range(ovl_lower_file, ovl_upper_file) on non samefs
will get -EXDEV from ovl_copy_file_range(), so will not fall back
to do_splice_direct().
We may be better off checking in_sb != out_sb and returning
-EOPNOTSUPP? not sure.
> + break;
> +
> + case OVL_CLONE:
> + ret = vfs_clone_file_range(real_in.file, pos_in,
> + real_out.file, pos_out, len);
> + break;
> +
> + case OVL_DEDUPE:
> + ret = vfs_dedupe_file_range_one(real_in.file, pos_in, len,
> + real_out.file, pos_out);
Problem:
real_out can be a readonly fd (for is_admin), so we will be deduping
the lower file.
I guess this problem is mitigated in current code by may_write_real().
How can we deal with that sort of "write leak" without patching
mnt_want_write_file()?
Thanks,
Amir.
next prev parent reply other threads:[~2018-04-17 20:31 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-12 15:07 [RFC PATCH 00/35] overlayfs: stack file operations Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 01/35] vfs: clean up dedup Miklos Szeredi
2018-04-12 16:25 ` Matthew Wilcox
2018-04-12 17:24 ` Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 02/35] vfs: add path_open() Miklos Szeredi
2018-04-12 16:38 ` Matthew Wilcox
2018-04-12 15:07 ` [RFC PATCH 03/35] vfs: optionally don't account file in nr_files Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 04/35] ovl: copy up times Miklos Szeredi
2018-04-13 8:25 ` Amir Goldstein
2018-04-13 14:23 ` Vivek Goyal
2018-04-12 15:07 ` [RFC PATCH 05/35] ovl: copy up inode flags Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 06/35] Revert "Revert "ovl: get_write_access() in truncate"" Miklos Szeredi
2018-04-12 15:07 ` [RFC PATCH 07/35] ovl: copy up file size as well Miklos Szeredi
2018-04-24 18:10 ` Vivek Goyal
2018-04-12 15:07 ` [RFC PATCH 08/35] ovl: deal with overlay files in ovl_d_real() Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 09/35] ovl: stack file ops Miklos Szeredi
2018-04-26 14:13 ` Vivek Goyal
2018-04-26 14:43 ` Miklos Szeredi
2018-04-26 14:56 ` Vivek Goyal
2018-04-26 15:01 ` Miklos Szeredi
2018-04-26 15:13 ` Vivek Goyal
2018-04-26 15:21 ` Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 10/35] ovl: add helper to return real file Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 11/35] ovl: readd read_iter Miklos Szeredi
2018-04-13 13:35 ` Amir Goldstein
2018-04-12 15:08 ` [RFC PATCH 12/35] ovl: readd write_iter Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 13/35] ovl: readd fsync Miklos Szeredi
2018-04-23 13:36 ` Vivek Goyal
2018-04-23 13:39 ` Miklos Szeredi
2018-04-23 13:53 ` Vivek Goyal
2018-04-23 14:09 ` Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 14/35] ovl: readd mmap Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 15/35] ovl: readd fallocate Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 16/35] ovl: readd lsattr/chattr support Miklos Szeredi
2018-04-13 14:48 ` Amir Goldstein
2018-04-17 19:51 ` Amir Goldstein
2018-04-22 8:35 ` Amir Goldstein
2018-04-22 15:18 ` Amir Goldstein
2018-04-23 10:21 ` Miklos Szeredi
2018-04-23 10:28 ` Miklos Szeredi
2018-04-23 6:11 ` Ritesh Harjani
2018-04-12 15:08 ` [RFC PATCH 17/35] ovl: readd fiemap Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 18/35] ovl: readd O_DIRECT support Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 19/35] ovl: readd reflink/copyfile/dedup support Miklos Szeredi
2018-04-17 20:31 ` Amir Goldstein [this message]
2018-04-18 8:39 ` Amir Goldstein
2018-05-03 16:04 ` Miklos Szeredi
2018-05-03 19:48 ` Amir Goldstein
2018-04-12 15:08 ` [RFC PATCH 20/35] vfs: don't open real Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 21/35] vfs: add f_op->pre_mmap() Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 22/35] ovl: copy-up on MAP_SHARED Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 23/35] vfs: simplify dentry_open() Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 24/35] Revert "ovl: fix relatime for directories" Miklos Szeredi
2018-04-13 14:02 ` Amir Goldstein
2018-04-13 15:55 ` Vivek Goyal
2018-04-12 15:08 ` [RFC PATCH 25/35] Revert "vfs: update ovl inode before relatime check" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 26/35] Revert "ovl: fix may_write_real() for overlayfs directories" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 27/35] Revert "ovl: don't allow writing ioctl on lower layer" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 28/35] Revert "vfs: add flags to d_real()" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 29/35] Revert "vfs: do get_write_access() on upper layer of overlayfs" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 30/35] Revert "vfs: make argument of d_real_inode() const" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 31/35] Revert "vfs: add d_real_inode() helper" Miklos Szeredi
2018-04-18 8:19 ` Amir Goldstein
2018-04-18 11:42 ` Miklos Szeredi
2018-04-18 13:38 ` Steven Rostedt
2018-04-18 13:49 ` Miklos Szeredi
2018-04-18 13:56 ` Steven Rostedt
2018-04-19 19:54 ` Vivek Goyal
2018-04-20 9:14 ` Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 32/35] Partially revert "locks: fix file locking on overlayfs" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 33/35] Revert "fsnotify: support overlayfs" Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 34/35] vfs: simplify d_op->d_real() Miklos Szeredi
2018-04-12 15:08 ` [RFC PATCH 35/35] ovl: fix documentation of non-standard behavior Miklos Szeredi
2018-04-13 11:23 ` Amir Goldstein
2018-04-25 14:49 ` [RFC PATCH 00/35] overlayfs: stack file operations J. R. Okajima
2018-04-25 19:44 ` Miklos Szeredi
2018-05-04 15:23 ` Miklos Szeredi
2018-05-05 16:37 ` Amir Goldstein
2018-05-08 14:25 ` Miklos Szeredi
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